That said, 1950s politics wasn't my history focus so I will defer w/o more of the facts.
Based upon what I did study of that era, the liberals were very much in ascendency as they would prove in the 1960s. I firmly believe the complacency of the US and the UK allowed Communist infiltration throughout the 30s and 40s. Joe highlighted that fact. Doesn't mean he wasn't an ass and a complete showman.
With all due respect, you could not be more wrong. McCarthy knew what was coming his way. He knew he would be trashed. He also knew the CPUSA had a contract out on his life. He said that from the start. He did it because someone had to do it. Republicans won the Congress in 1946 in a landslide because Truman and Democrats were losing country after country to communists. But even after that, Truman was dragging his feet and keeping known Soviet agents on in his administration.